Vibration isolator



Sept. 30,1947. w, A, LEA 2,428,285

VIBRATION ISOLA'I'OR Filed March l] 1946 if/ 5? 46 d mum s /N VENTORWALTER ALEXANDER LEA ATTORNEY Patented Sept. 30, 1947 UNITED STATESPATENT OFFICE VIBRATION ISOLATOR Walter Alexander Lea, Los Angeles,Calif., assignor to Frank H. Newton, Los Angeles, Calif.

Application March 11, 1946, Serial No. 653,544

3 Claims.

The invention relates to a therapeutic vibrator and to a method ofassembling the vibrator and has for an object to provide an improved andsimplified type of motor and eccentric for producing the vibration aswell as an improved full floating resilient support for the vibratingplatform, and an improved method of assembling the full floatingplatform on its base.

For further details of the invention reference may be made to thedrawing wherein Fig. 1 is a perspective view of a therapeutic vibratoraccording to the present invention, shown in an upsidedown position.

Fig. 2 is an enlarged sectional view of the motor of Fig. 1.

Fig. 3 is a view in elevation, partly in section and with parts brokenaway, showing one of the full floating spring suspensions of Fig. 1,Fig. 3 showing the device upsidedown.

Referring in detail to the drawings, the vibrator l of this inventioncomprises a base having thereon a full-floating vibratory platform 3,the device being shown upsidedown to illustrate the Working parts. Thebase 2 is in the form of a frame open at its top and bottom and having aplurality of spaced feet as indicated at 4 and 5, and the platform 3which is adapted to support the patient, covers the top of the frame andhas a depending flange 6 which extends over the vertical side wall 1 ofthe frame 2.

The platform 3 has a full floating resilient support on the base 2 andfor this purpose there are provided a plurality of sets, hereillustrated as four, spring suspensions, all alike, and one of which isindicated at 9 and shown enlarged in Fig. 3. As shown in Fig. 3, theplatform 3 has an upright elongated lug Ill having a cross arm lladjacent the bottom of side wall l and provided with a spring retainingnotch i2 and the base 2 has an elongated upright lug [3 having a crossarm I 4 adjacent the top of side wall 1 and provided with a springretaining notch l5. The lugs l and I3 are about as long as the height ofthe side wall I and are arranged inside of the side wall I. A helicalcoil spring l6 has its opposite ends engaged in the spring hangers ornotches l2 and I5. The spring I is an upwardly pulling tension springand tends to separate the platform 3 from the base 2. This tendency iscounterbalanced by a parallel downwardly pulling helical tension springll having one end thereof connected in a spring hanger is in a short lug[9 on base 2, and its other end engaged in a spring hanger 20 in a shortlug 2| on the platform 3.

The other four sets of spring suspensions like that shown in Fig. 3 areprovided at substantially the four corners of the device I, as indicatedat 9, 22, 23 and 24.

The tension of the springs l6 and ll is such that the weight of anaverage adult on platform 3 is not sufficient to force this platform tothe top 25 of the base 2, while the patient by pushing down on theplatform 3 can depress it enough to operate the switch 26 for the motor2i. Switch 26 has a switch arm 28 which rocks in bearings 29 and 30 onthe underside of the platform The switch arm 28 at its opposite ends hase2:- tensions 3| and 32 which bear against stops 33 and 34,respectively, on the opposite sides l of the frame 2. When the platform3 is tilted by stepping on either side or pushed towards the base 2, theswitch rod 28 is rocked to close switch 26 and connect a source ofalternating current, not shown, to the motor 21.

Motor 21 is adapted to be operated by the standard 110 volt, cycle,single phase current, commonly used for house lighting circuits. Motor21 is a self-starting induction type motor but is not of the ordinarytype in that the stator 35 as shown in Fig. 2, is an internal member andis surrounded by a rotor 36 in the form of a cylindrical shellcomprising an iron clad squirrel cage rotor.

The stator 35 has a central aperture 3i through which passes an axle 38which is supported by and held stationary in the supports 38 and 4G. Thestator 35 has a driven fit on or is suitably fixed to the stationaryaxle 38.

The stator 35 has four polar projections indicated at 4l-44. Around pole42 is a winding 45 and around pole 44 is a field winding 46. These twowindings 45, 46 magnetize the four poles. The field windings 45, 45 maybe connected in series together and with the A. C. supply. Each polell-44 is provided with a shad ing coil short-circuited on itself, theshading coil for pole 4| being indicated at 41 and the other three poles42-44 having a similarly positioned and arranged short-circuited shadingcoil. The shading coils like 41 remain short-circuited and theirconnections are not changed during the starting and running of themotor.

The rotor 21 is made up of a series of laminations of magnetic materialhaving embedded therein a squirrel cage of which one of the bars isindicated at 48. The opposite ends of the bars like 48 are suitablyshort-circuited for example by a cast lead ring 49 between the end ofthe rotor 21 and each end plate 50, 5|. End plate 5| may have a seriesof fan blades 52 to ventilate the stator 35 and rotor 36 through theopenings between the spaced feet such as 4 and 5 underneath the bottomof the imperforate surrounding side wall 1. End plate 50 carries abearing 53 and end plate 5| has a similar bearing, not shown, torotatably support the rotor 21 on the axle 38.

To cause the platform 3 to vibrate, there is attached to one end platesuch as 50 an arcuate weight 54 which serves as an eccentric.

The amount of vibration may be adjusted by varying the radial positionor amount of the weight 54. Its position may be varied by supporting iton one end by a pivot 55 and by securing the other end thereof to theend plate 50 by means of a screw 56 at a certain distance from the rotoraxis, or by fastening screw 56 in another hole 51 which is at adifferent distance from the rotor axis.

Preferably the motor 2'! is positioned with its axis extendinglengthwise of the middle of platform 3 with the eccentric 54 facing andadjacent the front end 58 of the platform.

In order to assemble the spring suspension, the base 2 is placed on topof the platform 3 as shown in Figs. 1 and 3, with the platform 3 fartheraway from base 2 than its normal floating position, and the springs like16 are inserted through the open bottom of frame 2 one at a time andpositioned in notches like I2 and I5, with springs [6 under little or notension. Then the base and platform are placed in a jig and pressure isapplied to urge platform 3 closer to base 2 than its normal floatingposition, thereby stretching springs IE to bring spring hangers l8 and20 close enough together so that springs like IT can be inserted throughthe open bottom of base 2 and mounted with little or no tension on thehangers like I8 and 20. Then the jig and pressure are removed and theplatform 3 floats on the four sets of springs like It and H, which thenexert their normal opposed tensions. Springs like 16 are more powerfulthan the springs like 11, because the springs like IE not only mustovercome the tension of springs like I! but also the weight of an adultperson or whatever portion of his body is supported by the platform 3.

It will be apparent that various modifications may be made in theinvention without departing from the spirit of the following claims.

I claim:

1. A therapeutic vibrator comprising a vibratory platform, a basetherefor comprising a frame open at the top and bottom and having avertical side wall, a plurality of spaced base lugs extending upwardlyfrom and inside of said side wall,

each of said base lugs having an upright portion having at one sidethereof a (first) spring hanger adjacent the bottom of said base andhaving at the other side thereof a cross arm having a (second) springhanger adjacent the top of said wall, said platform having dependingtherefrom a similar pair of lugs for each of said base lugs, one memberof each of said pairs being short and having a (third). spring hangerabove one of said first spring hangers, the other member of each of saidpairs having an elongated pendant portion having a cross arm having a(fourth) spring hanger adjacent the bottom of said wall below one ofsaid second spring hangers, a set of downwardly pulling tension springseach connected at one end to one of said first spring hangers and at itsother end to its companion third spring hanger, and a set of upwardlypulling tension springs each connected at one end to one of said secondspring hangers and at its other end to its companion fourth springhanger.

2. A therapeutic device comprising a base having a surrounding sidewall, said base having an open top and having a bottom having anenlarged opening therein, a vibratory platform covering said top, a fullfloating spring suspension for said platform inside of said side wall,said suspension comprising a. set of helical tension springs urging saidplatform to said base, and a second set of helical tension springsurging said platform away from said base, a group of short and longspring hangers on said base and a companion group of short and longspring hangers on said platform supporting said springs laterally spacedapart around said wall, with a short hanger of each group for a springof said first set and a long hanger of each group for a spring of saidsecond set, said opening in said base providing access to all of saidsprings.

3. A therapeutic device comprising a base frame having a surroundingside wall having an opening at the top and bottom thereof, a vibratoryplatform covering said top, and a full floating spring suspension forsaid platform inside of said side wall, said suspension comprising aplurality of pairs of tension springs connected to said base and to saidplatform in opposed relation.

WALTER ALEXANDER LEA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,234,770 Meyer Apr. 11, 19411,845,941 Stevens et a1 Feb. 16, 1932 2,235,158 Krenzke Mar. 18, 19412,235,183 Wettlaufer Mar. 18, 1941 2,368,727 Robinson Feb. 6, 1945653,906 Brown July 17, 1900

